Sewing machine motor mounting system



June 20, J GRAHAM SEWING MACHINE MOTOR MOUNTING SYSTEM 2 Sheets-Sheet 1Filed Aug. 21, 1964 INVENTOR. JAMES S GRAHAM WITNESS June Q, 197 J. s.GRAHAM 3,326,153

SEWING MACHINE MOTOR MOUNTING SYSTEM Filed Aug. 21, 1964 2 Sheets-Sheet2 I 3| 28 a a 27 38 :5 V 39 2e 37 INVENTOR. JAMES S. GRAHAM wjjyw .13

AT ORNEY Patented June 20, 1967 3326.158 SEWENG MACHINE MQTOR MOUNTINGSYSTEM James S. Graham, Glasgow, Scotland, assignor to The SingerCompany, New York, N.Y., a corporation of New Jer ey Filed Aug. 21,1964. Ser. No. 391.105 Claims priority, application Great Britain, May28, 1964, 22,022/64 1 Claim. (Cl. 112-220) This invention relates to asewing machine motor mounting system and more particularly to a meansfor mounting an electric motor outside the frame of a sewing machine.

In one type of conventional sewing machine, motive power is furnished byan electric motor which is mounted within the hollow sewing machineframe. With this arrangement the sewing machine frame serves to shieldthe motor from foreign particles and to prevent the operator of thesewing machine from viewing or contacting the electric motor or themotor mount. The electric motor, therefore, may be fabricated with askeleton frame and the arrangement of the motor mount need not satisfyaesthetic requirements.

When it is desirable or advantageous that the sewing machine electricdrive motor be located externally of the sewing machine frame, a problemarises in that the electrical components of the motor must be shieldedand the shield as well as the motor mount are both visible and exposedto physical contact by the operator.

In prior sewing machines which utilize an electric motor mountedexternally of the sewing machine frame, it is conventional to constructthe casing or other shield of the motor as an integral part of the motorand to utilize the motor casing to support the motor on the sewingmachine. It is not convenient, therefore, with this conventionalarrangement of construction and mounting of a drive motor externally ofthe sewing machine frame to utilize an electric motor with a skeletonframe of the type usually mounted internally of the sewing machineframe. It is usual therefore to employ a second line of motors forsewing machines having externally mounted motors with attendant highercosts of production caused by failure to take complete advantage oflower costs per unit with increased volume which is afforded by massproduction.

It is an object of this invention to provide a novel and effective meansfor mounting an electric drive motor outside the frame of a sewingmachine.

It is another object of this invention to provide a means for mountingoutside the sewing machine frame an electric motor of the type having askeleton frame usually intended for incorporation internally of themachine frame together with novel and effective provision for shieldingthe electric motor from foreign objects and to insulate the motor fromthe operator.

A still further object of the invention is toprovide a means inaccordance with the foregoing objects to adjust the distance betweencenters of the rotor shaft of the motor and the main drive shaft of thesewing machine.

The objects of this invention are accomplished by providing a motorsupport bracket having an extension which is adjustably secured byvertically disposed slideway means to the standard of a sewing machine.A skeletonized yet fully operative electric motor is connected to themotor support bracket by insulating means with the rotor shaft of themotor parallel to the main drive shaft of the sewing machine. All of theparts of the motor except the cover are ultimately connected to thefield core which acts as a central skeleton. A flexible belt is loopedtautly around pulleys connected to the rotor shaft and the main driveshaft and the distance between centers of the shafts is adjustable bythe adjustable connection of the motor support bracket to the slidewaymeans. The cover is secured to the motor support bracket in spacedrelation about the skeletonized motor.

.The foregoing arrangement permits skeletonized motors normally mountedwithin the sewing machine frame to be externally mounted. A skeletonizedmotor when thus externally mounted possesses numerous favorablecharacteristics. Because the cover is independent and spaced from themotor, there is much less chance of insulation breaking down between themotor and the cover causing the operator to receive an electrical shockfrom the cover. In fact, the cover, since it does not serve to supportthe motor can be conveniently composed of a nonconductive material suchas plastic chosen particularly to eliminate the danger of electricalshocks from the cover. Since the endless belt which is looped around thepulleys on the rotor shaft of the motor and the main drive shaft of thesewing machine is normally composed of a nonconductive material, themotor is insulated from the sewing machine as well. Another advantage isseen in that the cover is easily replaceable without disturbing theoperative mounted relation of the motor relatively to the sewingmachine.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claim, taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a standard-end elevational view of a sewing machineincorporating the present invention,

FIG. 2 is a fragmentary rear-side elevational view of the standard-endof the sewing machine of FIG. 1,

FIG. 3 is a vertical cross sectional view taken substan tially along theline 33 of FIG. 1, and

FIG. 4 is an exploded perspective view of the assembly of the motorcover to the motor support bracket.

With reference to the drawings, the invention is illustrated asincorporated in a conventional family-type sewing machine having a frameincluding a work supporting bed 10 with a hollow standard 11 rising fromone end. A hollow bracket arm v12 is connected to the top of thestandard and extends laterally over the work supporting bed.

Journaled in the hollow bracket arm 12 of the sewing machine is a maindrive shaft 13 which extends longitudinally through the hollow bracketarm. A handwheel 14 is secured to the standard-end of the main driveshaft, and formed in the handwheel is a pulley 15 which has a V-shapedgroove 16.

As shown in FIG. 3, a conventional A.C. series commutator-type motor 24is utilized with the invention. The motor is skeletonized yet fullyoperative and of the type that is mounted within the hollow standard ofmany sewing machines.

Briefly, the motor 20 has a field core 21 and field windings 22. Bearingbrackets 23, 24 are secured to opposed ends of the field core by meansof diametrically opposed screws 25. A rotor shaft 26 is journaled in thebearing brackets 23, 24 by means of bearings 27, 28 having sphericalbearing surfaces 29 and 30 respectively. The bearings 27, 28 are heldagainst the bearing brackets 23 and 24, respectively, by means ofbearing retainer springs 31 and 32. The spherical bearing surfaces ofthe bearings 27, 28 provide a self-aligning feature for the rotor shaft.

Pressed on the rotor shaft 26 is an armature core 33 containing armaturewindings 34. The armature windings are connected to a commutator 35secured on the rotor shaft. Brushes (not shown) are housed in a statorbox 36. An outboard cooling fan 37 is pressed onto one end of the rotorshaft, and a pulley 38 having a V-shaped groove 39 is connected to theother end of the rotor shaft. Thus, all of the internal parts of themotor are ultimately connected to the field core 21 which acts as acentral skeleton.

The aforesaid skeletonized motor 20 is mounted externally of the sewingmachine frame by means of a motor support bracket which takes the formof a substantially flat plate 50. The motor support bracket has anextension 51 with upper and lower reinforcing flanges 52 and 53,respectively. A transverse elongated slot 54 is formed in the extensionof the motor support bracket to mate with an elongated verticallydisposed machined boss or rib 55 on the standard-end of the standard 11of the sewing machine. An intermediate portion 56 of the groove in themotor support bracket is widened to clear the threads of an adjustingscrew 57 by which the motor support bracket is adjustably connected tothe standard. The adjusting screw 57 is provided with a spacer 58 topermit the hexagonal flange 59 of the adjusting screw to be convenientlygripped by a wrench.

The motor support bracket 58 has an aperture or hole 60 to clear the endof the rotor shaft 26 of the motor 20, and arcuate ventilation ports 61are spaced around the rotor shaft clearance hole 60. In addition, aneyelet 62 is formed in the motor support plate for a power cord, and agrommet 63 composed of an insulating material is disposed in the powercord eyelet 62.

The skeletonized motor 20 is mounted on the motor support bracket 50 bymeans of diametrically opposed screws 70 which extend through holes 71in the motor support bracket. The screws 70 engage a pair of insulat ingshock absorbers 72 which are in turn secured to the ends of the screws25 by which the bearing brackets 23, 24 are connected to the field core21. A V-belt 73 is looped tautly around the pulleys and 38 which aresecured on the main drive shaft 13 of the sewing machines and the rotorshaft 26 of the motor, respectively.

The skeletonized motor is covered by an independent cover 80 which isconnected by means of diametrically opposed screws 81 to tabs 82protruding from the motor support bracket 50. The motor cover 80 has aventilation duct 83 in one end to house the cooling fan 37 when thecover is connected to the motor support bracket. The ventilation duct 83communicates with a series of vertically disposed ventilation slots 84in the end of the cover. The cover is provided with a reinforcing rib 85and may be composed of metal, plastic, or any other suitable material.The nonintegral cover has the additional advantage that a conductivematerial may be coated on the inside 86 of the cover to shieldelectronic appliances such as radios and television sets from radiofrequency waves radiated by the motor. It would be very difiicult to socoat the inside of a cover which is integral with a motor because ofspatial and insulation complications.

In operation, the motor support bracket 50 with the skeletonized motorattached is adjusted vertically on the boss or rib 55 by means of theadjusting screw 57 to provide the correct amount of tension for theV-belt 73. If it should be desired to replace the motor cover 8t) forany reason, the motor cover can be easily removed from the motor supportbracket by loosening the screws 81. The ventilation slots 84 in the endof the cover and the 'ventilation ports 61 in the motor support bracketprovide cross ventilation for air pulled into the cover by the coolingfan 37.

lthough the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made by way of example andthat numerous changes in the details of construction and the combinationand arrangement of parts may be resorted to without departing from thespirit and the scope of the invention.

What is claimed is:

A motor mounting system for a sewing machine having a work-supportingbed, a hollow standard rising from one end of the work-supporting bed, asubstantially hori- Zontal hollow bracket arm at the top of the standardoverhanging the work-supporting bed, a shaft, means for journaling theshaft in the hollow bracket arm, a first pulley having a belt groovemounted on the shaft outside the standard on the side of the standardopposite from the overhang of the bracket arm, a belt, an elongatedsubstantially vertical boss having a tapped hole also outside thestandard on the side of the standard opposite from the overhang of thebracket arm, and a screw threaded into the tapped hole in the elongatedboss on the standard, said motor mounting system comprising a fieldcore, field windings on the field core, a bearing bracket connected toeach end of the field core, a bearing mounted on each bearing bracket, arotor shaft journaled in the bearings, an armature core mounted on therotor shaft, armature windings on the armature core, a commutatormounted on the armature shaft, a pair of brushes, means for mounting thebrushes on one of the bearing brackets so that the brushes contact thecommutator, a motor support bracket having an aperture formed therein,

, insulating means for connecting one of the bearing brackets to themotor support bracket with one end of the rotor shaft projecting throughthe aperture in the motor support bracket, a second pulley mounted onthe rotor shaft on the side of the motor support bracket opposite fromthe bearing brackets, an extension on the motor support bracket having atransverse elongated slot formed therein for adjustably mounting themotor support bracket on the screw in the tapped hole in the elongatedboss on the standard so that when the belt is looped around the firstand second pulleys the distance between the centers of the pulleys canbe adjusted, an independent motor cover, and means for mounting themotor cover on the motor support bracket in spaced relation from thebearing brackets, the field core, the field windings, the pair ofbrushes, the commutator, the armature windings, the armature core, andthe rotor shaft.

References Cited UNITED STATES PATENTS 1,520,949 12/1924 Hemleb.1,962,880 6/1934 Schwab et al. 2,298,155 1 0/1942 Perkins 112-220 X2,604,862 7/1952 Merson et al. 2,739,552 3/1956 Sailer 112-220 3,238,4343/1966 Blitz et al 31089 X OTHER REFERENCES Data Sheet #139, MagneticShield Div. Perfection Mica Co., dated May 1958, copy in class 310-85, 2pp.

PATRICK D. LAWSON, Primary Examiner.

JORDAN FRANKLIN, Examiner.

H. H. HUNTER, Assistant Examiner,

